The overall objective of our projects is to understand the interplay between ego development and family environments. In the next five years I plan to further develop the current interlocking studies on two major levels: methodological (family assessments, longitudinal analyses); and substantive (sequence analyses, new applications of the work to intensive study of chronically and acutely ill children and their families). The most important new phases of the work involve the application of new analytic techniques to understanding intrafamilial processes and the extension of the studies to new clinical samples. Three projects are described in this application. The projects are related in terms of their conceptual background and methods. All of our studies use a multivariate design which has cross-sectional and longitudinal components. Samples are early adolescents, from psychiatric, diabetic, and high school control groups. In addition to individual adolescents we also study their families. Major assessment techniques include: development measures (e.g. the Loevinger test); a clinical research interview coded for ego processes; and a family procedure which generates direct observation interaction data, then coded through our newly constructed Constraining and Enabling Coding System (CECS). The first project uses these techniques to follow (over 4 years) adolescents and their families from two patient samples and a control group. The second study addresses the influence of specific psychosocial factors upon the course of insulin-dependent diabetes in a cohort of newly-diagnosed adolescents. The third study follows a very large (over 400) sample of adolescent diabetics in terms of ego development and related personality variables over a multi-year period. Through systematic observation and assessment of adolescents from clinically defined samples, our intent is to detail important psychological and familial aspects of deviations in ego development. Such detailing has significant implications for clinical intervention through clarifying the impact of chronic illness upon adolescents and their families, as well as the influence of development upon illness management.